Conductor clamp



Dec. 19, 1967 E JR 3,358,953

CONDUCTOR CLAMP Filed Feb. 21, 1966 IN VENTOR.

Malcolm BefkemJl:

Af/amegs United States Patent 3,358,953 CONDUCTGR CLAMP Malcolm Bethea, .l'r., R0. Box 1407, Birmingham, Ala. 35201 Filed Feb. 21, 1966, Ser. No. 528,957 4 Claims. (Cl. 24874) ABSTRACT OF THE DISCLOSURE A conductor clamp having a curved load bearing area coated with a low friction material and having an uncoated surface on a clamping area of the clamp providing electrical contact with a conductor.

This invention relates to a conductor clamp and more prticularly to such a clamp which shall include improved means reducing frictional Wear of the conductor clamped therein.

A more specific object of my invention is to provide a conductor clamp of the character designated in which the load bearing area of the clamp is provided with means for lowering friction between the conductor and the clamp while the clamping area of the clamp is in direct contact with the conductor, thereby providing slip strength between the conductor and the clamp and at the same time providing electrical contact between the clamp and the conductor.

A further object of my invention is to provide a conductor clamp of the character designated which shall be extremely simple of construction and manufacture due to the fact that conventional conductor clamps may be modified in accordance with my invention to protect the external surfaces of the conductor against wear while the clamp still retains the required slip strength and electrical contact between the clamp and the conductor.

As is well known in the art to which my invention relates, considerable wear occurs between the conductor and the curved load bearing area of the clamp due to the relative movement between the conductor and the clamp. Not only is the bottom of the conductor worn by this relative movement of the conductor and clamp but the sides of the conductor move relative to the sides of the clamping groove to cause wear in this area of the conductor. A low friction member cannot be inserted between the entire surface of the clamp and the conductor due to the fact that the clamp would not have the required slip strength and there would be no electrical contact between the clamp and the conductor.

Briefly, my improved clamp comprises a protective coating on the load bearing area of the conductor receiving groove of the clamp. An uncoated surface is provided in the clamping area of the clamp whereby this area of the clamp and the conductor are in direct contact with each other to provide the required slip strength and electrical contact between the conductor and the clamp.

Apparatus embodying features of my invention is illustrated in the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a perspective view of my improved clamp, showing the keeper element and conductor in dotted lines;

FIG. 2 is a vertical, sectional view through the clamp, the keeper and conductor being omitted for the sake of clarity;

FIG. 3 is a vertical, sectional view through a dead end clamp showing a modified form of my invention;

FIG. 4 is a side elevational view, partly broken away and in section, showing another modified form of my invention;

FIG. 5 is a sectional view showing a further modified form of my invention; and,

FIG. 6 is a fragmental view showing a still further modified form of my invention.

Referring now to the drawings, I show in FIGS. 1 and 2 a suspension clamp embodying a body 10 having a longitudinally extending groove 11 therein for receiving a conductor, indicated in dotted lines at 12. The groove 11 is generally U-shaped, as viewed in cross section and is provided with a bottom wall 13 and upstanding side walls 14. A keeper 16, indicated in dotted lines, fits within the groove 11 and engages the opposite side of the conductor 12 from the side thereof engaged by the bottom wall 13 whereby the conductor is clamped between the keeper and the groove 11 in a manner well understood in the art. The keeper 16 is secured to the body 10 of the clamp by U-bolts 17 having the usual retaining nuts 18, as shown in FIG. 1.

The keeper l6 cooperates with the body 10 of the clamp to define a clamping area adjacent the longitudinal center of the groove ll. As shown in FIG. 2, this clamping area is shown as being between points A and B. The portions of the groove 11 outwardly of the points A and B are curved downwardly and outwardly to provide curved, load supporting areas outwardly of the points A and B.

To reduce frictional wear of the portions of the conductor engaging the curved, load bearing areas I provide a protective coating, such as a low friction coating 19, on the bottom wall 13 and side walls 14 from the point A to the outer ends of the body 10, as shown in FIG. 2. In like manner, I provide a protective coating 21 to the bottom wall 13 and side walls 14 of the clamp outwardly of the point B. Accordingly, the clamping area defined between points A and B is left uncoated whereby this clamping area is in direct contact with the conductor 12. The protective coatings 1? and 21 may be in the form of low friction coatings, such as a tetrafluoroethylene polymer. A suitable tetrafluoroethylene polymer is sold under the trade name Teflon.

In FIG. 6 of the drawing, I show a modified form of my invention in which the curved, load bearing area of the bottom wall 13 and side walls 14 of the clamp body 10 are coated with a resilient coating, such as an ozone resistant, chloroprene polymer. A suitable such chloroprene polymer is sold under the trade name Neoprene. The chloroprene polymer thus forms a resilient coating 22 from the point A in FIG. 6 to the outer end of the clamp body 10. Where the resilient coating 22 is employed instead of the tetrafiuoroethylene polymer coating, the coating tapers inwardly toward the point A, as shown in FIG. 6, whereby the coating 22 merges with the surface of the clamping section adjacent the point A. In actual practice, I have found that the thickness of the resilient coating 22 may be approximately one-eighth of an inch adjacent the outer ends of the clamp body 10.

In FIG. 3 of the drawing, I show a dead end clamp having a body 16*. A curved, outwardly opening groove I1 is provided in the clamp body 10 in position to receive a conductor 12 in the usual manner. Also, a keeper 16 fits within the groove Il and engages the conductor l2 as shown in FIG. 3. The usual U-bolt 17 and retaining nuts is hold the keeper 16 in clamping relation to the conductor. The keeper 16 thus defines a clamping area between the points A and B, the point A being adjacent the curved, load bearing area of the clamp body lti as clearly shown in FIG. 3. To reduce frictional wear of the portion of the conductor engaging the curved, load bearing area of the clamp body 10 1 coat the groove lir with a protective coating, such as a low friction coating 23 from a location adjacent the point A to the outer end of the curved, load bearing area, as shown. The protective coating 23 may be in the form of a tetrafluoroethylene polymer or in the form of a resilient chloroprene polymer as described hereinabove. Preferably,

Where the resilient chloroprene polymer is employed, the coating tapers inwardly toward a location adjacent the point A.

In FIG. 4 of the drawing, I show a clamp top insulator unit 24 having a clamp body 19* connected to the upper end thereof. A longitudinally extending conductor receiving groove 11* is provided in the clamp body 10*. The groove 11 is generally U-shaped as viewed in cross section and is provided with a bottom wall 13 and upstanding side walls 14 The clamping area is defined between points A and B, as described hereinabove. Also, curved, load bearing areas are provided adjacent each end of groove 11 outwardly of the points A and B. The bottom wall 13* and the side walls 14 outwardly of the points A and B are coated with a protective coating 26, as described hereinabove. Accordingly, the area between the points A and B is left uncoated to provide direct contact between the conductor and the clamp body 10*.

In FIG. of the drawing, I show another modified form of my invention in which a conductor 12 is secured to a clamp body by a keeper 16. The keeper is secured to the clamp body 10 by suitable U-bolts 17, having retaining nuts 18. The clamp body 10 is provided with a longitudinally extending conductor receiving groove 11 as described hereinabove. The inner surface of the conductor receiving groove 11 is coated with a protective material, as set forth hereinabove. To provide slip strength and electrical contact between the clamp and the conductor 12, the portion of the keeper 16 engaging the conductor 12 is uncoated and electrical contact is made through the keeper and U-bolts to the main body of the clamps.

From the foregoing description, the construction and operation of my improved conductor clamp will be readily understood. Where a tetrafiuoroethylene polymer is employed as the protective coating, a relatively thin coating is applied to the bottom wall 13 and the side walls 14 outwardly of the points A and B. That is, the thin coating is applied to the curved, load supporting area which is located outwardly of the clamping area of the clamp. Where the coating is in the form of a chloroprene polymer to form a resilient coating, the coating tapers inwardly towards the clamping area, as shown in FIG. 6, whereby the surface of the clamping area merges with the adjacent surface of the coating. In all embodiments of my invention, an uncoated, conductor engaging surface is provided in the clamping area to provide slip strength and electrical contact between the clamp and the conductor.

From the foregoing, it will be seen that I have devised an improved conductor clamp which reduces to a minimum frictional wear of the portions of a conductor which engage the curved, load bearing areas of the clamp attached thereto, as well as the contact areas between the sides of the conductor and the sides of the clamp. By providing a low friction coating for the conductor receiving groove outwardly of the clamping area of the groove, I reduce frictional Wear caused by motion between the conductor and the curved, supporting surface of the clamp. Also, by providing an uncoated surface in the clamping area of the clamp, I provide slip strength and at the same time provide electrical contact between the conductor and the clamp.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a conductor clamp embodying a body having a conductor receiving groove therein with a curved load bearing area adjacent at least one end thereof together with a cooperating keeper disposed to engage a conductor and define a clamping area adjacent said curved load bearing area, the improvement which comprises:

(a) a protective coating of low friction, non-conductive material carried by said load bearing area of said conductor receiving groove, and

(b) there being an uncoated surface on said clamping area disposed to engage a conductor and provide electrical contact therewith.

2. In a conductor clamp as defined in claim 1 in which said groove is generally U-shaped as viewed in cross section and the bottom and sides of said groove are coated with said protective coating from a point adjacent said keeper to the outer end of said curved load bearing area.

3. In a conductor clamp as defined in claim 1 in which the entire surface of said'groove is coated with said protective coating and a portion of the keeper which is disposed to engage the conductor is uncoated to provide direct contact between the keeper and the conductor.

4. In a conductor clamp as defined in claim 1 in which the protective coating comprises a tetrafluoroethylene polymer.

References Cited UNITED STATES PATENTS 2,775,422 12/1956 Von Herbulis et a1. 24-135 XR 2,984,441 5/1961 Dalmasso 174-'-42 XR 3,081,644 3/1963 Hudgens et a1.

FOREIGN PATENTS 465,488 5/ 1950 Canada.

ROY D. FRAZIER, Primary Examiner.

I. F. FOSS, Assistant Examiner. 

1. IN A CONDUCTOR CLAMP EMBODYING A BODY HAVING A CONDUCTOR RECEIVING GROOVE THEREIN WITH A CURVED LOAD BEARING AREA ADJACENT AT LEAST ONE END THEREOF TOGETHER WITH A COOPERATING KEEPER DISPOSED TO ENGAGE A CONDUCTOR AND DEFINE A CLAMPING AREA ADJACENT SAID CURVED LOAD BEARING AREA, THE IMPROVEMENT WHICH COMPRISES: (A) A PROTECTIVE COATING OF LOW FRICTION, NON-CONDUCTIVE MATERIAL CARRIED BY SAID LOAD BEARING AREA OF SAID CONDUCTOR RECEIVING GROOVE, AND (B) THERE BEING AN UNCOATED SURFACE ON SAID CLAMPING AREA DISPOSED TO ENGAGE A CONDUCTOR AND PROVIDE ELECTRICAL CONTACT THEREWITH. 